Apparatus and method for single-tone device discovery in wireless communication networks

ABSTRACT

Embodiments of wireless communication devices and methods for device discovery is generally described herein. Some of these embodiments describe an apparatus having processing circuitry arranged to configure a single-tone discovery signal for transmission in a symbol in a transmission opportunity based on an assignment pattern. The assignment pattern may define frequency positions, for a set of transmission opportunities, at which the apparatus shall transmit discovery signals in the corresponding transmission opportunity. The apparatus may have physical layer circuitry arranged to transmit the single-tone discovery signal in the corresponding transmission opportunity. Other methods and apparatuses are also described.

PRIORITY APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/142,021, filed Dec. 27, 2013, which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/748,706, filedJan. 3, 2013, and to U.S. Provisional Patent Application Ser. No.61/806,821, filed Mar. 29, 2013, each of which are incorporated hereinby reference in their entirety.

TECHNICAL FIELD

Embodiments pertain to wireless communications. Some embodiments pertainto wireless communications directly between two or more pieces of userequipment.

BACKGROUND

User Equipment (UE), including mobile devices such as phones, tablets,e-book readers, laptop computers, and the like, have become increasinglycommon. Accompanying the increase of usage of such devices has been anincrease in the usage of proximity-based applications and services.Proximity-based applications and services are based on the awarenessthat two or more devices/users are close to one another and desire tocommunicate to each other. Exemplary proximity-based applications andservices include social networking, mobile commerce, advertisement,gaming, and the like. Current systems for providing proximity-basedapplications may suffer from performance and interference-basedproblems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example wireless system including device-to-deviceusers operating and coexisting with traditional cellular users.

FIG. 2 illustrates an example of single tone transmission in accordancewith some embodiments.

FIG. 3 illustrates an example of device multiplexing and frequencyhopping in accordance with some embodiments.

FIG. 4 illustrates an example of frequency varying transmission forsingle-tone in accordance with some embodiments.

FIG. 5 illustrates an example of frequency varying transmission forsingle-tone that applies frequency hopping at the chunk or block levelin accordance with some embodiments.

FIG. 6 illustrates an example of applying frequency varying single-tonewith time domain OCC in accordance with some embodiments.

FIG. 7 illustrates an example of scrambling the single-tone basedtransmission in accordance with some embodiments.

FIG. 8A illustrates an example for simple extensions with copy at aphysical resource block level with position being unvarying inaccordance with some embodiments.

FIG. 8B illustrates an example for simple extensions with copy at aphysical resource block level with position being varying in accordancewith some embodiments.

FIG. 9 illustrates an example of chunk level frequency hopping withpattern-shifting across slots in accordance with some embodiments.

FIG. 10 illustrates single tone transmission spread across all OFDMsymbols in a slot or subframe in accordance with some embodiments.

FIG. 11 illustrates an example of a short range discovery signalaccordance with some embodiments.

FIG. 12 shows an example block diagram of a user equipment (UE),according to some embodiments described herein.

FIG. 13 is a block diagram showing details of an eNodeB according tosome embodiments described herein.

DETAILED DESCRIPTION

Proximity-based applications and services represent a fast growingsocial and technological trend that may have a major impact on theevolution of cellular wireless/mobile broadband technologies. Theseservices are based on awareness that two devices or two users are closeto each other and, thus, may be able to directly communicate with eachother. Proximity-based applications can include social networking,mobile commerce, advertisement, gaming, etc. These services andapplications stimulate the design and development of a new type ofdevice to device (D2D) communication that can be integrated into currentand next generation mobile broadband networks such as LTE andLTE-Advanced.

By leveraging direct connectivity between two devices in a network, D2Dcommunication can enable machines to communicate directly with oneanother.

Existing mobile broadband networks were designed to optimize performancemainly for human type of communications and thus are not optimized forD2D specific requirements. For example, existing mobile networks do notsupport the establishment of direct links between two devices. Theefficient support and seamless integration of D2D communication incurrent and future mobile broadband technologies can encourageenhancements or modifications across different layers (e.g., PHY andMAC) in order to optimally address the future D2D demands, meetperformance requirements, and overcome technical challenges.

In some embodiments, D2D users can operate in a co-existing mode andreuse the spectrum with other cellular users. FIG. 1 illustrates anexample wireless system 100 including D2D users (a typical few labeled101) operating and coexisting with traditional cellular users. Unlikethe existing traditional LTE network infrastructure, D2D users 101 donot necessarily need to communicate via the central coordinator (eNodeB)102. In some embodiments, the D2D users 101 can communicate directlywith each other or through hops 103 of other D2D users. When D2Dcommunication shares the same resources with the mobile broadbandsystem, certain functions can still be controlled and coordinated by theeNodeB 102 of the mobile broadband network such as when centralizedcontrol offers more benefits.

In some embodiments, proximity sensing methods can be implemented by thenetwork through monitoring the UE attachment/association to a particularcell or using location based services and protocols. In addition tothese traditional methods, new proximity based functionality can beadded to the functions of the D2D coordinator 105. For example, aspecial device discovery zone can be allocated in the D2D transmissionregion where device discovery signaling is used to assist in D2D clusterorganization and D2D link establishment. A special discovery signaltransmission interval can be introduced in the D2D transmission regionfor that purpose. Additionally, proximity sensing can be based on D2Dlink quality measurements.

Small cells using low power nodes may help operators handle increasedmobile traffic. A low-power node may transmit using less power thannodes of macro node and base station (BS) classes. For example a homeeNodeB (e.g., pico eNodeB or femto eNodeB) 104 may serve as a low-powernode in some embodiments. By providing small cell (e.g. home eNodeB 104)enhancements, some embodiments may provide improved performance andreduced interference for both indoor and outdoor hotspots.

Small cell enhancement may be provided either with or without coverageby a macro eNodeB (e.g. eNodeB 102). Accordingly, two or more carrierfrequencies may be used for a UE 111 that is served by multiple eNodeBs,pico eNodeBs, home eNodeBs, etc. Embodiments may provide small cellenhancements in both indoor and outdoor deployments, in sparse and densecells, and with both non-ideal and close-to-ideal backhaul.

Small cell enhancement according to some embodiments should improvenetwork energy efficiency for systems of most levels of complexity andwith traffic characteristics according to characteristics currently seenin small cells. In some embodiments, one or more small cells can beplaced in a dormant mode such that some small cells do not serve anyactive users, in order to maintain network energy efficiency whilemaintaining thresholds of user throughput and capacity per unit area.

Some embodiments provide for discovery mechanisms between devices (e.g.,D2D discovery) and between home eNodeBs and other small cells and userdevices (e.g., small cell discovery).

Embodiments can be applied in orthogonal frequency-division multiplexing(OFDM)-based systems and in single-carrier frequency division multipleaccess (SC-FDMA)-based systems.

FIG. 2 illustrates an example of single tone transmission in accordancewith some embodiments. In FIG. 2, a single tone transmission 201 canoccur at subcarrier index k=1 with periodicity T. A given UE 101(FIG. 1) or other equipment can use one subcarrier for transmission,while not using other subcarriers for transmission within the same OFDMsymbol or SC-FDMA symbol duration. Single-tone transmissions can providefavorable Peak-to-Average Power Ratios (PAPR) and Cubic Metric (CM)properties based on signal fluctuation of the sinusoidal waveform of thesingle-tone transmission in the time domain. In embodiments that providelower PAPR or CM, wider coverage can be provided at least because lesspower back-off is required in the Power Amplifier (PA). A UE 101 can useother subcarriers for transmission to other UEs 101, home eNodeBs 104,or other devices in a frequency division multiplexing (FDM) manner.Further, other subcarriers of an OFDM symbol or an SC-FDMA symbol can beassigned for other UEs 101, home eNodeBs 104, etc., to transmit singletone signals in a time division multiplexing (TDM) manner. Thetransmitted subcarrier and/or periodicity can be configured orpredetermined based on certain rules, e.g. based device identities (e.g.cell ID for home eNodeBs 104 or other small cells, UE ID for UEs 101 orD2D ID for D2D discovery).

Some embodiments may implement frequency hopping across slots may toachieve frequency diversity gains. FIG. 3 illustrates an example ofdevice multiplexing and frequency hopping in accordance with someembodiments.

Some embodiments can implement frequency hopping in a mirrored hoppingdesign for improved frequency diversity. For example, in theillustrative example of FIG. 3, if Device 0 transmits a signal in slot 0in one physical resource block (PRB), device 0 may transmit the samesignal in slot 0 of other PRBs available for transmission.

Receiver circuitry of UE 101, home eNodeB 104 or other unit that is toreceive signals as described herein may perform a Fast Fourier Transform(FFT) algorithm to convert the time domain signal to the frequencydomain signal, and perform a power measurement to detect the existenceof a transmitted signal in a given OFDM symbol or SC-FDMA symbol.

Transmission by additional UEs 101 can be multiplexed in a given OFDMsymbol or SC-FDMA symbol by allocating or assigning additional PRBs forUE 101 transmission. In an example, up to twelve UEs 101 can bemultiplexed for simultaneous discovery signal transmission in one PRBassuming that all OFDM (or SC-FDMA) symbols within a slot can be usedfor single-tone transmission.

However, single-tone transmission may suffer from signal fading when theassigned single tone experiences deep fading. Further, at least becausethe assigned subcarrier for single tone transmission may be reused byanother UE 101, home eNodeB 104, or other device, the likelihood ofinterference (e.g., collision) among transmissions can be high.Additionally, the transmitted energy, which can affect coverage area, isin accordance with the number of OFDM (or SC-FDMA) symbols fortransmission, and therefore single-tone transmissions in current systemscan exhibit elevated levels of transmitted energy.

Some embodiments can help overcome drawbacks related to deep fading orelevated energy levels by varying the frequency position k for singletone transmission at every transmission opportunity while maintainingsingle-carrier properties of low CM or PAPR. An assignment pattern atwhich frequency positions will vary can be predetermined, for example inspecifications according to a standard of the 3rd Generation PartnershipProject (3GPP) family of standards, or the assignment pattern can beconfigured in a Radio Resource Control (RRC) message, algorithm, etc. Insome embodiments, the assignment pattern can be generated in apseudo-random sequence (e.g. Gold sequence). Accordingly, even when asingle-tone based signal falls into the deep fading in a certaintransmission opportunity, deep fading can be overcome in anothertransmission opportunity with better channel conditions by exploitingfrequency diversity.

FIG. 4 illustrates an example of frequency varying transmission forsingle-tone in accordance with some embodiments. The transmit position401 can be represented within a PRB by:r(k,l)=mod(k+l+ID,N _(SC))  (1)where k is the subcarrier index, l is the OFDM symbol index, ID is anidentifier for the UE 101 or home eNodeB 104, or other unit performingthe single-tone transmission, and N_(SC) is the number of subcarrierswithin an assigned region (e.g. assigned PRB).

FIG. 5 illustrates an example of frequency varying transmission forsingle-tone that applies frequency hopping at the chunk or block levelin accordance with some embodiments. In the illustrative example, achunk/block may be equivalent to a PRB or a set of PRBs. Frequencyhopping can occur across slots. For example, as illustrated in FIG. 5,the hopping pattern can be mirrored within the given bandwidth so thatthe maximum frequency diversity can be achieved. The discovery signalregion can be defined at the edge of the given bandwidth.

In embodiments described herein regarding FIGS. 3 and 5, themultiplexing capacity may be reduced. For example, the multiplexingcapacities for the structures of FIG. 3 and of FIG. 5 within a PRB innormal cyclic prefix (NCP) are, respectively, 84 (=12 subcarriers times7 symbols) and 12. Some embodiments increase multiplexing capacity andcoverage (e.g., energy) by applying Orthogonal Code Cover (OCC), on eachSC-FDMA symbol (or OFDM symbol). Some embodiments alternatively providephase rotational sequence (e.g., cyclic shift) on each SC-FDMA or OFDMsymbol. FIG. 6 illustrates an example of applying frequency varyingsingle-tone with time domain OCC in accordance with some embodiments.

If a discrete Fourier transform code or phase rotational sequence isapplied for OCC, the code can be expressed as

$\begin{matrix}{W_{n}^{k} = e^{\frac{j\; 2\pi\;{kn}}{N}}} & (2)\end{matrix}$where N=7, k=0 . . . 6, and n=0 . . . 6, and where it is understood bythose of ordinary skill in the art that phase rotational sequence in thefrequency domain is equivalent to cyclic shift operation in the timedomain.

To overcome interference collision, in example embodiments, the singletone can be populated by the sequence generated by a predeterminedpattern. The predetermined pattern may be generated, in someembodiments, by a pseudo-random sequence. In other embodiments, thepopulated sequence can be generated according to the QuadraturePhase-Shift Keying (QPSK)-based base sequence, which is currentlydefined in 3GPP TS 36.211 for demodulation reference signals (DM RS) andphysical uplink control channels (PUCCH). The sequence length can betruncated in some embodiments, or otherwise adapted by cyclic extendingone or more sequence elements. If the sequences are de-spread in apredictable fashion, the interference can be randomized from thespreading gain. Therefore, the discovery signal can be transmitted inone or more OFDM symbols (e.g., each OFDM symbol in a subframe) orSC-FDMA symbols, and the transmitted single-tones can be populatedwithin a subframe or a slot of a subframe. The scrambled sequence can bebinary phase-shift keying (BPSK)-based, QPSK-based, polynomial based, orcomplex value based.

An example of sequence population of single-tone transmission can beQPSK modulated signals generated by a pseudo random sequence (e.g., GoldSequence). As an additional example, a sequence can be generatedaccording to:

$\begin{matrix}{r_{l} = {{\frac{1}{\sqrt{2}}\left( {1 - {2 \times {c(0)}}} \right)} + {j\frac{1}{\sqrt{2}}\left( {1 - {2 \times {c(1)}}} \right)}}} & (3)\end{matrix}$where c_(init)=f(l,n_(s),id), such that the generated pseudo randomsequence is at least a function of OFDM symbol index l, slot numbern_(s), or ID of the home eNodeB 104, UE 101, D2D ID, group ID, etc.

FIG. 7 illustrates an example of scrambling the single-tone basedtransmission in accordance with some embodiments. It is noted that thescrambling on single tone transmission can be applied to otherembodiments described herein.

In some embodiments, the concatenation of the multiple RBs (e.g., units)for single tone transmission can be conducted to capture more frequencysamples. In some embodiments, the signal location for transmission mayvary although embodiments are not limited thereto. FIG. 8A illustratesan example for simple extensions with copy and for the extension at aPRB level (e.g., 12 subcarriers) with position being unvarying within aunit, while FIG. 8B illustrates an example that includes the positionvarying within a unit.

FIG. 9 illustrates an example of chunk level frequency hopping withpattern-shifting across slots in accordance with some embodiments.According to some embodiments, coverage can be improved by transmittingsignals in different OFDM (SC-FDMA) symbol. Further, in someembodiments, at every OFDM (SC-FDMA) symbol, one tone is used fortransmission and the transmitted tone can vary from OFDM (SC-FDMA)symbol to OFDM (SC-FDMA) symbol. The transmitted tone location for a UE101, home NodeB 104, or other device may be configured or predeterminedaccording to device IDs (e.g. cell ID or device ID). The sequencemodulation can be performed over the signal tone. The composition of thesignals in a slot or a subframe in some embodiments covers the largestpossible frequency range in the RB in order to provide improvedauto-correlation profiles. Further, as shown in FIG. 9, the chunk/block(RB) level hopping can be performed in slot level. OCC can be applied toincrease multiplexing capacity as described herein.

In some embodiments, the single tone can be spread out across more thanone (e.g., all) OFDM symbols or SC-FDMA symbols within a slot or withina subframe as shown in FIG. 10. Additionally, OCC can be applied inthese embodiments.

In some embodiments, mode configuration (e.g. by RRC signaling) betweenshort (e.g., mode 1) and long (e.g., mode 2) range modes is provided.The discovery signal density of mode 2 can be higher (in the timedomain) than mode 1 to support wider coverage. For instance, mode 1 canbe used for the smaller range of the detection and mode 2 can be usedfor the wider range of the detection. There can be a trade-off betweenthe multiplexing capacity and the coverage.

FIG. 11 illustrates an example of mode 1 in accordance with someembodiments. FIG. 9 illustrates an example of mode 2 in accordance withsome embodiments. The multiplexing capacity of mode 1 is 84 (=12*7)while that of mode 2 is 12. The larger coverage can be achieved withmode 2 with the cost of lower capacity.

Example Device for Implementing Embodiments

FIG. 12 is a block diagram of the basic components of a UE 1200 inaccordance with some embodiments. The UE 1200 may be suitable as a UE101 (FIG. 1). The UE 1200 may support methods for single-tone baseddiscovery signaling in accordance with embodiments described above withrespect to FIG. 1-11.

The UE 1200 includes one or more antennas 1210 arranged to communicatewith home eNodeB 104 (FIG. 1), or other types of wireless local areanetwork (WLAN) access points. The UE 1200 further includes a processor1220, instructions 1225, and a memory 1230. The UE 1200 may furtherinclude a communications interface 1240. In one embodiment, the memory1230 includes, but is not limited to, random access memory (RAM),dynamic RAM (DRAM), static RAM (SRAM), synchronous DRAM (SDRAM), doubledata rate (DDR) SDRAM (DDR-SDRAM), or any device capable of supportinghigh-speed buffering of data.

The processor 1220 may include logic or code to enable the UE 1200 toprocess signals received from the network through the antenna 1210. Theprocessor 1220 may include code or other instructions 1225 to allow theUE 1200 to configure a single-tone discovery signal for transmission ina symbol in a transmission opportunity based on an assignment pattern,the assignment pattern defining frequency positions, for a set oftransmission opportunities, at which the apparatus shall transmitdiscovery signals in the corresponding transmission opportunity. Theprocessor 1220 can retrieve the assignment pattern from a radio resourcecontrol (RRC) message defined in accordance with a standard of the 3GPPfamily of standards. The assignment pattern may be configured based on arule in accordance with a standard of the 3GPP family of standards. Therule may be based on identification information or type information forthe UE 1200.

The assignment pattern can define frequency positions in a first set ofRBs for a first subset of the set of transmission opportunities, and ina second set of RBs for a second subset of the set of transmissionopportunities. The first set of RBs can include at least one RB that isnot included in the second set of RBs. The processor 1220 can apply anOCC algorithm or a phase rotational sequence algorithm to the symbol.

The instructions 1225 can allow the UE 1200 to determine that fading hasoccurred in a first symbol in a first transmission opportunity in whichthe UE 1200 has transmitted a discovery signal. The processor 1220 canthen configure discovery information for transmission in a subsequenttransmission opportunity and in a second symbol at a different frequencyposition than that of the first symbol, the second symbol beingdetermined based on the assignment pattern.

Example embodiments allow a UE 1200 to transmit the single-tonediscovery signal in the corresponding transmission opportunity using thecommunications interface 1240.

Example eNodeB for Implementing Embodiments

FIG. 13 is a block diagram showing details of an eNodeB 1300 accordingto some embodiments. The eNodeB 1300 may be suitable as home eNodeB 104(FIG. 1), eNodeB 102 (FIG. 1), etc. The eNodeB 1300 includes a processor1310, a memory 1320, a transceiver 1330, and instructions 1335. TheeNodeB 1300 may include other elements (not shown).

The processor 1310 comprises one or more central processing units(CPUs), graphics processing units (GPUs), or both. The processor 1310provides processing and control functionalities for the eNodeB 1300.Memory 1320 comprises one or more transient and static memory unitsconfigured to store instructions 1335 and data for the eNodeB 1300.

The transceiver 1330 comprises one or more transceivers including amultiple-input and multiple-output (MIMO) antenna to support MIMOcommunications. The transceiver 1330 receives UL transmissions andtransmits DL transmissions, among other things, from and to UE 101 (FIG.1).

The processor 1310 can generate a first assignment pattern for discoverysignal transmission by a UE 101 in a cell served by the eNodeB 1300. Thefirst assignment pattern can define frequency positions, in transmissionopportunities, at which the UE 101 is permitted to transmit discoverysignals in a corresponding transmission opportunity. A transmissionopportunity can include a number of frequency positions, and theprocessor 1310 can generate the first assignment pattern such that, in atime interval including a plurality of transmission opportunities, theUE 101 transmits a discovery signal at least once in each of the numberof frequency positions. The processor 1310 can generate a secondassignment pattern upon receiving an indication that additional UEs haveentered the cell served by the eNodeB 1300. The second assignmentpattern can include assignment information for each UE in the cell.

The transceiver can transmit a RRC signal to the UE 101 that includesinformation for the first assignment pattern.

The instructions 1335 comprise one or more sets of instructions orsoftware executed on a computing device (or machine) to cause suchcomputing device (or machine) to perform any of the methodologiesdiscussed herein. The instructions 1335 (also referred to as computer-or machine-executable instructions) may reside, completely or at leastpartially, within the processor 1310 and/or the memory 1320 duringexecution thereof by the eNodeB 1300. The processor 1310 and memory 1320also comprise machine-readable media.

As those of ordinary skill in the art will readily appreciate, variousaspects described throughout this disclosure may be extended to othertelecommunication systems, network architectures and communicationstandards. By way of non-limiting example, various aspects may beextended to other Universal Mobile Telecommunications System (UMTS)systems. Various aspects can be used in systems employing Long TermEvolution (LTE) (in FDD, TDD, or both modes), and LTE-Advanced (LTE-A)(in FDD, TDD, or both modes).

Examples, as described herein, may include, or may operate on, logic ora number of components, components, or mechanisms. Components aretangible entities capable of performing specified operations and may beconfigured or arranged in a certain manner. In an example, circuits maybe arranged (e.g. internally or with respect to external entities suchas other circuits) in a specified manner as a component. In an example,the whole or part of one or more computer systems (e.g. a standalone,client or server computer system) or one or more hardware processors maybe configured by firmware or software (e.g. instructions, an applicationportion, or an application) as a component that operates to performspecified operations. In an example, the software may reside (1) on anon-transitory machine-readable medium or (2) in a transmission signal.In an example, the software, when executed by the underlying hardware ofthe component, causes the hardware to perform the specified operations.

Accordingly, the terms “component” and “component” are understood toencompass a tangible entity, be that an entity that is physicallyconstructed, specifically configured (e.g. hardwired), or temporarily(e.g. transitorily) configured (e.g. programmed) to operate in aspecified manner or to perform part or all of any operation describedherein. Considering examples in which components are temporarilyconfigured, one instantiation of a component may not existsimultaneously with another instantiation of the same or differentcomponent. For example, where the components comprise a general-purposehardware processor configured using software, the general-purposehardware processor may be configured as respective different componentsat different times. Accordingly, software may configure a hardwareprocessor, for example, to constitute a particular component at oneinstance of time and to constitute a different component at a differentinstance of time.

Additional examples of the presently described method, system, anddevice embodiments include the following, non-limiting configurations.Each of the following non-limiting examples may stand on its own, or maybe combined in any permutation or combination with any one or more ofthe other examples provided below or throughout the present disclosure.The preceding description and the drawings sufficiently illustratespecific embodiments to enable those of ordinary skill in the art topractice them. Other embodiments may incorporate structural, logical,electrical, process, and other changes. Portions and features of someembodiments may be included in, or substituted for, those of otherembodiments.

The Abstract is provided to comply with 37 C.F.R. Section 1.72(b)requiring an abstract that will allow the reader to ascertain the natureand gist of the technical disclosure. It is submitted with theunderstanding that it will not be used to limit or interpret the scopeor meaning of the claims. The following claims are hereby incorporatedinto the detailed description, with each claim standing on its own as aseparate embodiment.

We claim:
 1. An apparatus of a user equipment (UE) configured fortransmission of a single-tone discovery signal with a frequency hoppingtechnique, the apparatus comprising: processing circuitry configured to:decode Radio Resource Control (RRC) signaling, the RRC signaling toconfigure the UE for the transmission of the single-tone discoverysignal with the frequency hopping technique, the RRC signalingcomprising information for determining a frequency location ofsubcarriers allocated to a first set of resource blocks and informationfor determining a subcarrier index; encode the single-tone discoverysignal comprising a symbol for transmission on a single tone inaccordance with the information for determining the frequency locationof the subcarriers allocated to the first set of resource blocks and theinformation for determining the subcarrier index; and configure aphysical layer to transmit the single-tone discovery signal in a subsetof the first set of resource blocks according to the information fordetermining the frequency location of subcarriers allocated to the firstset of resource blocks and the information for determining thesubcarrier index; and memory configured to store the information fordetermining the frequency location of subcarriers allocated to the firstset of resource blocks and the information for determining thesubcarrier index, wherein the processing circuitry is further configuredto determine a first resource block within the first set of resourceblocks based on the frequency location and determine an initialsubcarrier within the first resource block based on the subcarrier indexfor transmission of the single-tone discovery signal, wherein theprocessing circuitry is further configured to determine subsequentsubcarriers for transmission of the single-tone discovery signal inaccordance with the frequency hopping technique among subcarriers withinother resource blocks of the first set of resource blocks based on thesubcarrier index, and wherein the processing circuitry is furtherconfigured to apply an orthogonal code coverage (OCC) algorithm or aphase rotational sequence algorithm to the symbol.
 2. The apparatus ofclaim 1, wherein the symbol is part of a symbol group encoded fortransmission in accordance with the information for determining thefrequency location of subcarriers allocated to the first set of resourceblocks and the information for determining the subcarrier index.
 3. Theapparatus of claim 1, wherein the frequency location of subcarriersallocated to the first set of resource blocks varies from a frequencylocation of subcarriers allocated to a second set of resource blocks. 4.The apparatus of claim 1, wherein the frequency location of subcarriersallocated to the first set of resource blocks is configured based onidentification information associated with the apparatus.
 5. Theapparatus of claim 1, wherein the frequency location of subcarriersallocated to the first set of resource blocks is configured based ontype information associated with the apparatus.
 6. The apparatus ofclaim 3, wherein the first set of resource blocks includes at least oneresource block that is not included in the second set of resourceblocks.
 7. The apparatus of claim 1, wherein the processing circuitry isfurther configured to determine that fading has occurred in a firstsymbol in which the apparatus has transmitted the single-tone discoverysignal; and configure discovery information for transmission in a secondsymbol at a different frequency location than that of the first symbol,wherein the processing circuitry determines the frequency location ofthe second symbol based on one or more of the information fordetermining the frequency location of the subcarriers allocated to thefirst set of resource blocks and the information for determining thesubcarrier index.
 8. A computer-readable hardware storage device thatstores instructions for execution by one or more processors of a userequipment (UE) configured for transmission of a single-tone discoverysignal with a frequency hopping technique, the instructions to configurethe one or more processors to: decode Radio Resource Control (RRC)signaling, the RRC signaling to configure the UE for the transmission ofthe single-tone discovery signal with the frequency hopping technique,the RRC signaling comprising information for determining a frequencylocation of subcarriers allocated to a first set of resource blocks andinformation for determining, a subcarrier index; encode the single-tonediscovery signal comprising a symbol for transmission on a single tonein accordance with the information for determining the frequencylocation of the subcarriers allocated to the first set of resourceblocks and the information for determining the subcarrier index;configure a physical layer to transmit the single-tone discovery signalin a subset of the first set of resource blocks according to theinformation for determining the frequency location of subcarriersallocated to the first set of resource blocks and the information fordetermining the subcarrier index; determine a first resource blockwithin the first set of resource blocks based on the frequency locationand determines an initial subcarrier within the first resource blockbased on the subcarrier index for transmission of the single-tonediscovery signal, determine subsequent subcarriers for transmission ofthe single-tone discovery signal in accordance with the frequencyhopping technique among subcarriers within other resource blocks of thefirst set of resource blocks based on the subcarrier index; and apply anorthogonal code coverage (OCC) algorithm or a phase rotational sequencealgorithm to the symbol.
 9. The computer-readable hardware storagedevice of claim 8, wherein the symbol is part of a symbol group encodedfor transmission in accordance with the information for determining thefrequency location of subcarriers allocated to the first set of resourceblocks and the information for determining the subcarrier index.
 10. Thecomputer-readable hardware storage device of claim 8, wherein thefrequency location of subcarriers allocated to the first set of resourceblocks varies from a frequency location of subcarriers allocated to asecond set of resource blocks.
 11. The computer-readable hardwarestorage device of claim 10, wherein the first set of resource blocksincludes at least one resource block that is not included in the secondset of resource blocks.
 12. The computer-readable hardware storagedevice of claim 8, wherein the frequency location of subcarriersallocated to the first set of resource blocks is configured based onidentification information associated with the UE.
 13. Thecomputer-readable hardware storage device of claim 8, wherein thefrequency location of subcarriers allocated to the first set of resourceblocks is configured based on type information associated with the UE.14. The computer-readable hardware storage device of claim 8, whereinthe instructions are further to configure the one or more processors to:determine that fading has occurred in a first symbol in which the UE hastransmitted the single-tone discovery signal; and configure discoveryinformation for transmission in a second symbol at a different frequencylocation than that of the first symbol, wherein the instructions arefurther to configure the one or more processors to determine thefrequency location of the second symbol based on one or more of theinformation for determining the frequency location of the subcarriersallocated to the first set of resource blocks and the information fordetermining the subcarrier index.